1. UML 2.0 OCL Specification, Object Management Group, Inc. (2005)
2. Baru, C., Gupta, A., Ludäscher, B., Marciano, R., Papakonstantinou, Y., Velikhov, P., Chu, V.: XML-Based Information Mediation with MIX. In: Proceedings of SIGMOD 1999, Philadelphia, PA, pp. 597–599 (1999)
3. Lecture Notes in Computer Science;S. Bowers,2002
4. Carey, M.J., Haas, L.M., Schwarz, P.M., Arya, M., Cody, W.F., Fagin, R., Flickner, M., Luniewski, A.W., Niblack, W., Petkovic, D., Thomas, J., Williams, J.H., Wimmers, E.L.: Towards heterogeneous multimedia information systems: The Garlic approach (1994)
5. Casanova, M.A., Tucherman, L., Lima, M.J.D., Netto, J.L.R., Rodriguez, N.R., Soares, L.F.G.: The Nested Context Model for Hyperdocuments. In: Proceedings of Hypertext 1991, San Antonio, Texas, pp. 193–201 (1991)